Lateral Flow Analyzer Timing With Incubation-Insensitive Cutoff
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Solution Overview
Problem
Lateral flow assay devices read by instruments face issues with timing, as they may be read after excessive incubation, leading to invalid or incorrect results due to superior sensitivity, unlike devices read by the naked eye.
Innovation Solution
A system comprising a test device with two populations of detectable particles and an analyzer that uses an optical system to determine a cut-off value, insensitive to incubation time, by calculating a ratio or transforming signals from these particles to accurately detect the presence or absence of an analyte.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If lateral flow assay devices are read by instruments with superior sensitivity, then detection accuracy is improved, but the devices may be read after excessive incubation leading to invalid results
Solution Approach 1:
The patent applies preliminary action by incorporating a timer signal or line into the assay device before the actual test is performed. This timer mechanism is pre-positioned to automatically generate a signal after a predetermined time interval, alerting the user to read the result at the optimal moment before excessive incubation degrades reliability. This resolves the contradiction by enabling instrument-level detection accuracy while preventing timing-related validity issues through pre-built temporal control.
Solution Approach 2:
The patent implements feedback by using the timer signal as a real-time indicator that guides when to read the result. The timer line provides continuous temporal feedback during the incubation process, signaling when the optimal reading time has been reached. This feedback mechanism ensures that instruments read results at the correct time window, maintaining both high detection accuracy and result validity by preventing reads after excessive incubation.
2Duration of action of moving object
If lateral flow assay devices are read by the naked eye, then incubation time can be extended, but detection sensitivity is reduced
Solution Approach 1:
The timer signal or line is incorporated in advance into the assay device structure, creating a predetermined temporal marker that indicates when results should be read. This preliminary temporal guidance allows naked-eye readers to optimize their reading time, extending incubation sufficiently for visible signal development while preventing excessive incubation that would degrade sensitivity. The timer mechanism is pre-positioned to provide this optimal reading window guidance.
Solution Approach 2:
The timer line utilizes color change or visual signal development to indicate the optimal reading time. This visual timer signal changes state (e.g., develops color or becomes visible) after a predetermined time interval, providing a clear visual cue to readers. This allows extended incubation for sufficient signal accumulation while preventing excessive incubation through the visual timer indicator, thereby maintaining detection sensitivity for naked-eye reading.
3Loss of time
If a timer signal is incorporated into the assay device, then reading timing is controlled, but device complexity increases
Solution Approach 1:
The timer signal or line serves multiple functions within the assay device: it acts as both a procedural control element and a temporal indicator for result reading. By making the timer component multi-functional (serving as both a timing mechanism and a visual guide), the patent reduces the need for separate dedicated timer components, thereby controlling reading timing while minimizing the increase in device complexity. The timer line integrates timing control into the existing assay structure rather than adding entirely separate systems.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Ensures accurate and timely detection of analytes in lateral flow immunoassay devices, independent of incubation time, providing reliable results.
Implementation Method 1
an analyzer that uses an optical system to determine a cut-off value, insensitive to incubation time, by calculating a ratio or transforming signals from these particles
Implementation Method 2
The labeled binding reagent is then typically captured at a test zone by a second reagent having specific binding for a second binding site of the analyte of interest
Implementation Method 3
A liquid sample, such as a biological sample from a human or an environmental sample, is applied to one end of the porous strip and the capillary properties of the strip transports the liquid sample along the strip
Data Source
AI summary
A system comprised of an apparatus and a test device is described. The test device and the apparatus are designed to interact to determine the presence or absence of an analyte of interest in a sample placed on the test device. The test device and apparatus interact to provide a timer feature for determining a test device specific adjustable cut-off value that is used to ascertain whether signal from a test line in the device corresponds to a positive or negative results, irrespective of the time elapsed since placement of sample on the test device. The adjustable cut-off value renders the system relatively insensitive to incubation time of the test device, where if the incubation time is shorter or longer than needed for accuracy of a test result, the analyzer will report an invalid result, thus preventing the reporting of an incorrect (false negative or false positive) result.